package com.qxy.practice.collection.Tree;


import lombok.val;
import java.util.Arrays;
import java.util.List;
import java.util.Vector;

class TreeNode2 {
     int val;
     TreeNode2 left;
     TreeNode2 right;
     TreeNode2() {}
     TreeNode2(int val) { this.val = val; }
     TreeNode2(int val, TreeNode2 left, TreeNode2 right) {
         this.val = val;
         this.left = left;
         this.right = right;
     }
 }
class Solution2 {
    private List<Integer> arr = new Vector<>();
    private int min = Integer.MIN_VALUE;


}